SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bf27484ac8d943700a6088f2746816575b7237617d6743f00173d3edbadd658' 
  AND token = 'MfBdwRcpfs9lorwpVyArBlvxLymV2ynmtpyRR1ivzpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}